Atrial fibrillation (AF) affects 5.2 million Americans and over 75% of AF patients are 65 years or older. Weighing stroke risk against risk of bleeding from anticoagulants (AC) is central to AF management. Older AF patients are at highest risk for stroke and major bleeding, often curtailing prescription of AC. Therapy for AF has also become more complex in recent years with the introduction of target specific oral anticoagulants beyond warfarin. In the proposed Systematic Assessment of Geriatric Elements in Atrial Fibrillation (SAGE-AF) study, our overall objective is to enhance AC decision-making in older patients with AF by assessing previously neglected information that is part of a geriatric assessment (e.g., cognitive function, fall risk) and identifying its key elements amenable to administration in the clinic and associated with important AC outcomes (e.g., bleeding, time in therapeutic range [TTR], patient-reported AC satisfaction). We will conduct geriatric assessments every 6 months for 2 years in a diverse sample of 1,200 older AF patients at high stroke risk (CHA2DS2-VASc?2) recruited from 5 ambulatory clinics in Central MA and GA. The specific Aims of the proposed project are: 1. Relate components of a geriatric assessment, based on validated measures of psychosocial and cognitive function and frailty, to use and type of AC, and compare how elements of the geriatric assessment change over time in AC users and non-users. 2. Among AF patients receiving AC, relate geriatric assessment measures at baseline to indicators of successful AC (e.g., bleeding, TTR, and patient satisfaction), 3. Among AF patients receiving AC, relate change in geriatric assessment measures to indicators of successful AC (bleeding, TTR and patient satisfaction) and evaluate whether this association varies by AC type. Our findings will contribute important information on novel and parsimonious risk stratifiers for optimal anticoagulation and clinical and quality of life outcomes in older patients with AF. We will also disseminate our results in a novel and user-friendly was by preparing a concise, easy to use geriatric AF resource based on our results that is comprised of key geriatric elements, all of which will be freely available in the public domain, and instructions for administration and interpretation. This Geriatric AF Resource will accelerate the uptake of our findings and enhance the clinical impact of SAGE-AF.